Csomo - those ovaled holes on the trans arms will cause shift problems, but I've never seen'em cause the jam between 1 & 2 - there are bronze/oilite bushings that fix that problem up quick and easy
Larry - the adjustments shown in the shop manual are important, but also do not cause or cure the jamming - may have to be fiddled with after rebuilding the shift box, but mostly only a problem if the shifter has been off the column and apart
of the 6+ 60's trucks I've had, every one did that gear jam, always at the worst times, and every one was due to problems in the shift box - start there shor, fine-tune the rest after you cure the locking up problem!
Bill
